Well, of course, allergies can cause red eyes. Generally speaking,, there are some allergies resources which can just lead to eye allergies. And then your eyes will turn red, itchy, and even bloodshot. And at this time, you need to pay more attention to your eyes, for it will just make some disorders in your eyes, leading to more serious problems too. For example, you should try to find the reason of red eyes. And then try some ways to avoid them. In common, you can just have some warm compresses which can be done in a long term. And that can be effective. Also, wearing a pair of eye patch is good too.